A clarification, I see that three quarters of people don't quite know what's going on as far as the AUR goes. This post is intended to clarify. Some portions are quoted from an explantion I gave someone else. (deja vu )

If you were not aware (like most people) that the AUR was made up of two sections, I'll clarify.
Everything in the AUR has a location, right now, either "community" or "unsupported". Things in "unsupported" are only available in PKGBUILD form, as they come from unknown sources, users submit them.
Everything in "community" is maintained by a TU (Trusted User), and so is safe, and available in binary form for pacman to download at:

[community]
Server = ftp://ftp.archlinux.org/community/os/i686/

In addition to the notion of package locations, the AUR puts users into classes. These classes include Developer, Trusted User, and User. They have varying levels of power and access within the AUR. Developers have ultimate power and access, and may perform any action (just about). Trusted Users are one step down, and have access to the community package CVS, as well as are able to create binary packages and add them to community. They also watch over the AUR, and have power to delete any unsavory comments or dangerous packages. Lastly, the user, which is most of you. This is the class that you are assigned if you just signed up for an account. You have the power to own packages in unsupported, upload them (PKGBUILDs ONLY), adopt them, abandon them, vote for them, comment on them..etc.

In addition to all this, the AUR has a notion of ownership as far as packages go. When a user submits a package, they are marked as the "maintainer" aka owner, for our purposes. They are then responsible for keeping it up to date and healthy. If a user no longer wishes to take care of a package, it should be abandoned so that others may take over and make use of it.